knowing combi's , from my past experience it may have a position sensor malfunction? Most of the units i've worked on when the steering has a centering issue it has to do with the sensors not picking up or may be out of adjustment or something to that effect.
But like richard said, you should call combi and don't assume anything.

Hi Gusstone,
As you are in Canada, can you contact the Combilift US based Technical Team. They are based in Greenboro NC. If you go to www.combilift.com, scroll to the very bottom, you can submit a "Technical Support" request. The form asks for truck SN, contact tel no,etc to help identify the problem and to contact you back. The tech team will then contact you. Here is a direct link here https://warranty.combilift.net/technical-support-form/

Hope this helps,
Richard